Regardless of the fabrication process, metal matrix composites (MMCs) require shaping to final dimensions and polishing to achieve specified surface roughness. Polishing, encompassing all finishing processes to minimize surface roughness and irregularities, is particularly challenging when the reinforcement phase consists of hard materials such as diamond particles. This study explores the feasibility of femtosecond (fs) laser polishing for copper/diamond (Cu/D) composite surfaces, aiming to achieve submicron average roughness. Two polishing methods were explored: top surface polishing, with the laser incidence perpendicular to the surface, and sidewall polishing, with the laser incidence parallel to the surface. In top surface polishing, the difference in ablation thresholds of Cu and diamond leads to 'mushroom' structures, with diamond protruding from the Cu matrix. In sidewall polishing, a 4 degrees incidence angle with 2000 scanning repetitions per millimeter reduced initial roughness by 96.5 %, achieving a final roughness of 0.72 mu m. Moreover, fs laser polishing preserves the crystalline structure of the D phase.

Disposable coffee cups, with over 50 billion consumed annually in the United States and hundreds of billions used globally each year, represent a substantial yet underrecognized source of consumer exposure to micro- and nanoscale particles (MNPs). Here we quantify MNP release from commercial coffee cups under consumer-relevant conditions and evaluate the cytotoxicity of particles derived from cup materials. MNP release was strongly influenced by temperature, exposure time, and agitation. Under extreme conditions (85 °C and vigorous agitation), nanoparticle concentration reached 6.7 ± 1.7 × 108 particles mL-1 (n = 3, p < 0.01), exceeding microscale particle concentrations by approximately 2–3 orders of magnitude. Pre-use rinsing reduced particle release by 75 ± 10% (range: 65–85%, n = 3, p < 0.001), consistent with removal of loosely adhered residues. Raman spectroscopy identified predominantly polyethylene (PE) and polypropylene (PP) within microscale particles, while AFM-IR analyses revealed heterogeneous chemical signatures at nanoscale indicating contributions from both the PE liner and the cellulosic substrate. Scanning electron microscopy showed irregular, fractured morphologies indicative of thermal and mechanical degradation. Cup liner-derived PE fragments induced dose- and time-dependent cytotoxicity in human kidney proximal tubule epithelial (HK-2) cells, with a 72 h IC50 of 271.6 µg mL-1 (95% CI: 129.00–850.70 µg mL-1, R2=0.88) and caused time-dependent hemolysis in red blood cells (17% after 4 h at 1000 µg mL-1). Together, these findings identify disposable coffee cups as a source of micro- and nanoscale particle exposure and highlight practical mitigation and materials-design considerations.

Defect-induced non-radiative losses currently limit the performance of lead-free Cs3Cu2I5 perovskites. Despite extensive investigations, the identity of the defects responsible for experimentally observed nonradiative recombination remains controversial. Here, combining hybrid-functional first-principles calculations with complementary experiments, we quantitatively identify iodine vacancies (VI) as the dominant nonradiative recombination centers in Cs3Cu2I5. Guided by the elucidated defect-formation mechanism, the introduction of Ga reshapes both the thermodynamic and electronic landscape of Cs3Cu2I5, effectively suppressing the formation of deep-level VI during both nucleation and operation and restoring efficient self-trapped-exciton-mediated radiative recombination. Moreover, the as-formed Ga interstitials chemically diminish metal-halide antibonding coupling and rigidify the Cu-I framework, substantially enhancing resistance to structural decomposition. As a result, Ga-doped Cs3Cu2I5 nanocrystals exhibit significantly enhanced stability and achieve an ultrahigh photoluminescence quantum yield of 95.7%. The resulting deep-blue- and ultraviolet-pumped white light-emitting devices deliver stable emission with a high color rendering index of 95.3 and operational lifetimes exceeding 312 h. Our study unveils the critical but overlooked role of intrinsic electric conductivity characteristics in governing defect formation mechanisms in semiconductors in general. It may also provide a route to enhance the carrier lifetimes and efficiencies of lead-free Cu-based halide perovskites by defect passivation.

Precise construction of high-density single-atom active centers on polymeric semiconductors, together with concurrent regulation of their interfacial charge-transfer behavior, remains a central challenge for both photocatalytic energy conversion and neuromorphic electronics. Yet conventional wet photodeposition routes suffer from solvent-induced coordination distortion, defect formation, and limited metal dispersion. Here, we report a solvent-free dry-state in situ photoreduction strategy that anchors atomically dispersed Pt onto highly crystalline carbon nitride (AD-Pt-HCCN), achieving a Pt precursor conversion efficiency of 70.5%, which is 5.5 times higher than that of wet photodeposition. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM), X-ray photoelectron spectroscopy (XPS), and X-ray absorption fine structure (XAFS) collectively confirm uniformly distributed Pt single atoms coordinated in a quasi-fivefold configuration within triazine-heptazine frameworks. This coordination environment suppresses the formation of a classical nanoparticle-induced Schottky-type barrier and promotes ultrafast interfacial charge extraction, as supported by femtosecond transient absorption (fs-TA), photoluminescence (PL), time-resolved PL (TRPL), and electrochemical impedance spectroscopy (EIS) analyses. As a result, a photocatalytic H2 evolution rate of 5.8 mmolu00B7gu22121u00B7hu22121 is achieved, outperforming the counterpart prepared by conventional wet photodeposition (3.8 mmolu00B7gu22121u00B7hu22121), owing to the synergistic contributions of the increased Pt loading efficiency and the enhanced interfacial charge transfer induced by atomically dispersed Pt sites. Remarkably, the same atomic Pt sites serve as efficient charge-modulation centers in neuromorphic transistors, enabling pronounced excitatory postsynaptic current (EPSC)/inhibitory postsynaptic current (IPSC) responses, robust long-term potentiation/depression (LTP/LTD), and linear, hardware-relevant synaptic weight updates. Integrating experimentally extracted conductance states into an artificial neural network (ANN) framework yields high recognition accuracy of 98.6%, highlighting the broad potential of AD-Pt-HCCN as a multifunctional building block for energy-intelligence convergence.

Rapid technological advancements and the growing focus on sustainable practices have significantly expanded the potential applications of aluminum (Al) and its alloys, leading to a steady increase in demand over the years. This study investigated the densification of Al and Al-based materials using pressure-less liquid-phase sintering. Samples with 4–20 vol.% AlSi12 sintered at 640 °C for 1 h achieved the highest relative density (RD) and the lowest global porosity (GP) without exhibiting any shape deformation. In general, increasing the amount of sintering aid improves the density of the samples. This was confirmed by microstructural analysis using SEM, which revealed the progression of density—from initial particle coalescence at 4 vol.% AlSi12 to the development of microstructures with filled pores and well-defined grain boundaries at 20 vol.% AlSi12. X-ray diffraction (XRD) analysis also revealed an expanded lattice parameter, with minimal microstrain and a crystallite size closely resembling those of the initial Al powder. Samples with a relative density greater than 90% demonstrated thermal conductivities ranging from 170 to 200 W/mK and an average hardness of 29 HV5. Densification was further enhanced by increasing the compaction pressure from 50 MPa to 100–200 MPa for samples containing 12–20 vol.% AlSi12. The Al-based material compacted at 200 MPa and with 15 vol.% AlSi12 achieved the highest RD of approximately 99%. It exhibited a thermal conductivity of 195 W/mK at 30 °C and 190 W/mK at 70 °C, along with a hardness of 30 HV5.

This study explores the use of laser shock peening (LSP) to enhance material properties and high-temperature performance of fiber-sensor-fused smart parts fabricated by additive manufacturing (AM) methods. Using embedded fiber sensors as distributed strain gauges, the study demonstrates that LSP can induce compressive strains of up to 130 µε on fiber embedded 1-mm below metal surfaces. The electron backscatter diffraction (EBSD) analysis shows that, with optimized LSP parameters, the metallic matrix undergoes substantial microstructural refinement, resulting in denser structures. Thermal cycling tests showed that the LSP process can increase fiber slippage temperatures by more than 50 oC. This work shows that the LSP process is an effective room-temperature process for enhancing both surface quality and increasing fiber slippage threshold under both thermal and mechanical stress.

Laser-Induced Breakdown Spectroscopy (LIBS) has been widely used across industries, medical applications, and environmental monitoring for elemental identification and concentration analysis due to its high accuracy, speed, and efficiency. Beyond elemental identification and concentration analysis, many studies suggest that LIBS signal intensities are influenced by sample surface temperatures, presenting an opportunity for temperature monitoring in processes such as three-dimensional additive manufacturing. In such applications, accurately detecting local temperatures at printing spots of interest is critical, specifically in ceramic printing, where phase transitions require temperatures exceeding one thousand degrees Celsius. Due to the dynamic nature of plasma emissions and experimental variability, there are few reports on the use of LIBS for monitoring sample surface temperatures. The direct use of absolute LIBS intensities is challenging for this purpose. Instead, this study explored the use of intensity ratios for surface temperature estimation. A series of LIBS spectra over wavelengths from 430.96 to 438.99 nm were collected from zirconium carbide (ZrC) at temperatures ranging from 350 to 600 degrees C. Intensity ratios, including atomic-to-atomic, ionization-to-ionization, and atomic-to-ionization line ratios, were evaluated. These ratios demonstrated significant exponential correlations with surface temperatures. Among the regression models, the highest R-squared (R2) value of 0.976 was observed for the intensity ratio of Zr II 435.974 nm to Zr I 434.789 nm. Additionally, machine learning algorithms were applied for full LIBS spectrum analysis, enabling comprehensive classification and prediction of sample surface temperatures without relying solely on a single intensity ratio. This strategy has demonstrated the potential of machine learning-assisted LIBS for real-time detection of sample surface temperatures in complex and dynamic environments.

The preparation of superhydrophobic polypropylene (PP) surfaces for biosafety is a pressing challenge in the food and medical industries. We achieve superhydrophobicity on commercial PP using a single-step process based on femtosecond (fs) laser-induced micro/nano texturing in n-hexadecane. Analysis of the wetting behavior after fs laser texturing revealed that 120 times of repetitive texturing, with a contact angle (CA) exceeding 150 degrees and a rolling angle below 1 degrees yielded optimal results. The generation, growth, and evolution of micro/nanostructures over processing times were investigated to establish a direct correlation between the micro/nanostructures and hydrophobicity. Furthermore, we elucidated the interactions between fs laser pulses and different material types in air, water, and n-hexadecane to explain the formation of micro/nanostructures formed in n-hexadecane.

Understanding the behavior of polymer foams at high energy density conditions is crucial to advance inertial fusion energy research. Here, we present a new experimental platform designed to measure the thermodynamic state of these materials at megabar pressures. At the Matter in Extreme Conditions Endstation of the Linac Coherent Light Source, we heat samples using an optical, high-intensity, femtosecond laser and dynamically probe them with ultra-short, coherent x-ray pulses of high peak brightness. We perform x-ray Thomson scattering measurements in forward and backward scattering geometries to capture both collective and non-collective electron behavior in the sample. Simultaneously, x-ray fluorescence spectroscopy is used to measure the emission from a mid-Z dopant, providing complementary information on the plasma conditions. By combining these techniques, we obtain temporally resolved temperature measurements of the transient warm dense matter states. Our initial experiments designed to benchmark the platform with carbon samples yielded data resolving the ultrafast response to laser heating with sub-picosecond resolution, measuring plasma temperatures exceeding 50 eV. These findings lay the foundation for precision studies of the dynamic evolution of laser-heated polymer foams.

Among additive manufacturing (AM) methods, extrusion-based AM (EAM) stands out for its design flexibility and material efficiency, gaining attention for printing objects without requiring high temperature during deposition. This study investigates the fabrication of aluminum and aluminum alloy components using an extrusion-based 3D printing approach, employing a butanol-based paste formulation. The butanol binder minimizes oxidation, improves rheological properties, and ensures smooth extrusion and shape retention prior to post-processing. Printed structures undergo subsequent debinding and sintering to remove the gel part and enhance densification. An optimization of the debinding and sintering cycle is also investigated. Finally, the printing of aluminum–silicon alloys further improves sample densification using liquid-phase sintering. The findings demonstrate butanol-based paste extrusion as a promising method for manufacturing complex aluminum components, with potential applications in aerospace, automotive, and industrial sectors.

Novel compositionally complex borides, (Hf,Zr,Nb,Ti)B 2 and (Hf,Zr,Nb,Ti)B 2 ‒LaB 6 , were fabricated using spark plasma sintering process. (Hf,Zr,Nb,Ti)B 2 ‒LaB 6 exhibits a dual‐phase microstructure, in which (Hf,Zr,Nb,Ti)B 2 is a primary phase with the hexagonal structure and LaB 6 is a secondary phase with a cubic structure. The mechanical properties of both (Hf,Zr,Nb,Ti)B 2 and (Hf,Zr,Nb,Ti)B 2 ‒LaB 6 are comparable, with a combination of high hardness and moderate fracture toughness. Thermal diffusivity and conductivity of (Hf,Zr,Nb,Ti)B 2 are much lower than the individual transition metal borides but are significantly increased by the addition of LaB 6 . Herein, it is implied that the thermal properties of boride ceramics can be controlled through the appropriate design of principal metal element compositions.

Novel compositionally complex borides, (Hf,Zr,Nb,Ti)B2 and (Hf,Zr,Nb,Ti)B2-LaB6, were fabricated using spark plasma sintering process. (Hf,Zr,Nb,Ti)B2-LaB6 exhibits a dual-phase microstructure, in which (Hf,Zr,Nb,Ti)B2 is a primary phase with the hexagonal structure and LaB6 is a secondary phase with a cubic structure. The mechanical properties of both (Hf,Zr,Nb,Ti)B2 and (Hf,Zr,Nb,Ti)B2-LaB6 are comparable, with a combination of high hardness and moderate fracture toughness. Thermal diffusivity and conductivity of (Hf,Zr,Nb,Ti)B2 are much lower than the individual transition metal borides but are significantly increased by the addition of LaB6. Herein, it is implied that the thermal properties of boride ceramics can be controlled through the appropriate design of principal metal element compositions.

Over the past few years, femtosecond (fs) laser processing has drawn a growing interest in a wide range of applications as it offers the possibility to process the surface morphologies of metals and semiconductors. In contrast to other polishing techniques, laser polishing offers a flexible and non-contact solution, thereby avoiding potential external contamination, while enabling a precise selection of processing areas. We investigated the influence of fs laser parameters on surface roughness of pure copper and ablation thickness, focusing on highlighting the importance of fluence and scanning overlap. With a two-step processing strategy, composed of coarse and fine polishing steps, surfaces with Sa < 400 nm were achieved, representing a 98% reduction from the high roughness of 15 mu m on initial surfaces. This research demonstrated the possibility of directly polishing rough parts using a fs laser with a perpendicular incidence.

The additive manufacturing of metal matrix composites (MMCs) using laser powder bed fusion (LPBF) is gaining considerable attention for its ability to produce high‐performance materials with intricate geometries. However, incorporating reinforcement such as diamond (D) particles poses challenges to the melting and solidification behavior of the powders, potentially affecting print quality. In this study, the laser irradiation of AlSi10Mg powder mixed with 5 vol% of uncoated D particles is investigated across varying processing parameters. Dense (97%) and crack‐free parts are successfully produced using high laser powers (300 and 400 W) and low laser scanning speeds (300 and 400 mm s−1). It is shown that the energy needed for proper melting of the powder surpasses that required for printing pure AlSi10Mg. Scanning transmission electron microscopy coupled with energy‐dispersive X‐ray spectroscopy uncovers a direct interfacial reaction between the molten aluminum (Al) and the D reinforcement, forming Al carbide at the Al–D interface. Moreover, Al composites processed under optimal energy density exhibit an enhanced Young's modulus. It is highlighted that optimizing LPBF processing parameters is crucial to achieve superior material properties in MMCs, while controlled matrix–reinforcement interactions offer the potential for tailored properties.

Aluminum/carbon composites have garnered significant attention due to their promising thermal and mechanical properties. However, traditional manufacturing processes typically involve high-pressure techniques to achieve part densification, rendering them costly and less practical for large-scale applications. In this study, aluminum-AlSi12/diamond composites were produced using a pressureless, liquid-phase sintering technique. By carefully optimizing the sintering parameters, the densification of the composites reached 86%. Notably, this was further improved to 94% when the diamond particles were coated with copper, demonstrating the benefits of surface modification in enhancing densification. This innovative approach highlights the potential of free sintering as an effective method to achieve high-density composites without resorting to expensive high-pressure methods.

In the pursuit of advanced ceramic materials with exceptional irradiation-resistance and high-temperature tolerance for nuclear applications, compositionally complex carbides (CCCs) have emerged as a highly promising class of candidate materials for extreme environments. In such conditions, critical material properties such as thermal stability, elasticity, thermal conductivity and thermodynamics behavior are predominantly influenced by phonons. In CCCs, pronounced cation disorder can lead to significant phonon scattering due to inherent mass and force constant variations, impacting these critical properties. In this study, we used ab initio calculations to predict the phonon band structures and systematically explore the influence of mass and force constant variance on the phonon spectral function of CCCs with a rock salt structure, ranging from binary to five-metal component carbides. Our findings reveal that the selection and concentration of constituent elements can be strategically utilized to tune the phonon band structure, phonon bandgap and phonon scattering in CCCs, thereby enabling control over phonon-related properties. Additionally, we measured the thermal conductivity of some of these CCCs using the spatial-domain thermoreflectance technique. Interestingly, the measured thermal conductivity of some of these CCCs indicates that five-component ceramics exhibit higher thermal conductivity than certain ternary and binary alloys. This observation contrasts with the expectation that greater cation disorder would result in more scattering and lower thermal conductivity. This intriguing result opens up the possibility of discovering CCCs with better thermal conductivity, presenting new opportunities for their application in extreme environments.

The consistent rise in current density within electrical wires leads to progressively more substantial heat losses attributed to the Joule effect. Consequently, mitigating the electrical resistivity of copper wires becomes imperative. To attain this objective, the development of a composite material that incorporates a more conductive reinforcement, like graphene, holds great promise. The conception of a copper/graphene composite using a powder metallurgy-based approach is presented. An optimum graphene quantity of 0.06 vol.% was obtained by calculation in order to limit the phenomenon of overlapping layers. This synthesis technique enables the dispersion of graphene and the meticulous control of the interface through the growth of CuO(Cu) nanoparticles that are tightly bonded to the reinforcement. The increase in the hardness of the various materials with separation of the graphene sheets by ultrasonic treatment (55.3 to 67.6 HV) was obtained. It is an indicator of the correct distribution of the reinforcement. The influence on the electrical properties of dendritic copper (ρe = 2.30 µΩ.cm) remains limited, resulting in a modest reduction in electrical resistance of around 1.4%. Nevertheless, for flake copper (2.71 µΩ.cm) and brass (7.66 µΩ.cm), we achieved a more substantial reduction of 2.7% and 10%, respectively. With the improvement of graphene quality, there exists a greater potential for further enhancing the electrical properties.